Epigenetics Flashcards
Why is cellular plasticity important
Allows cells to change from different states and possess different phenotypes. Important in Development, differentiation and response to stress or injury
What is epigenetics
A stable, heritable phenotype resulting from changes in a chromasome without altering the physical DNA sequence
Ouline the structure of DNA
A DNA double helix is coiled around a histone protein. 8 histones come together to form a nucleosome. Multiple nucleosomes fold to produce a chromatin fibre called a solenoid. This is further looped and compressed to form chromatin which is packed into a chromatid. 2 chromatids come together to form a chromasome.
What is a histone
A positively charged protein which is used for a negatively charged DNA double helix to coil around. DNA winds around 8 core histones
What is chromatin
A complex of DNA and proteins which forms chromasomes within the nuclus of eukaryotic cells
What 2 forms does chromatin exist in
Heterochromatin - Closed, highly condesned and has
low transcriptional activity
Euchromatin - Open, loosley packaged
High transcriptional activity
Subject to histone
methylation/acetylation
What is epigenomics
The study of the complete set of epigenetic alterations
What are the 3 main types of epigenetic modification
DNA methylation
Histone modification
Chromatin remodeling
Give an example of DNA hypermethylation
X-chromasome inactivaion in the Calico cat by DNA hypermethylation = due to random X inactivation of X chromasomes in females.
